16
75
– 95: Magnetite and other minerals of black iron
The goal of determining soil composition is to eliminate constant audio signals while searching for
objects. In some cases, the sound cannot be eliminated. After automatic soil composition, some users
may want to adjust the sensitivity to their own needs.
For manual adjustment:
•
Switch the detector to ALL METAL mode.
•
Move the coil up and down, as with automatic soil composition detection.
•
Use the + and - buttons to set the desired value.
If the soil composition is set incorrectly, you will hear different tones as the coil moves up and down.
•
If the tones are louder as you move the coil up, increase the value.
•
If the tones are louder as you move the coil down, decrease the value.
Note:
Experienced users prefer a setting where they get a low response when lowering the coil.
POSITIVE AND NEGATIVE RESPONSE
The reason to set good values for soil composition is so that you are not disturbed by minerals in the
soil. If the setting is not correct, the minerals in the soil will announce positive or negative tones
according to the incorrect value.
POSITIVE RESPONSE
If the GND BAL number is too high, the response to soil minerals will be positive. This means that if
you move the coil down in PINPOINT or ALL METAL mode, the tone will be louder as the coil
approaches the ground. The tone will be weaker as you lift the probe off the ground.
NEGATIVE RESPONSE
If the GND BAL number is too low, the response to soil minerals will be negative. This means that if
you move the probe down in PINPOINT or ALL METAL mode, the tone will not be heard as the probe
approaches the ground. The tone will be louder as you lift the probe off the ground.
Fe
3
O
4
PANEL
This panel shows the amount of Fe
3
O
4
mineralization. This information is updated every second. The
data is sensitive to movement and gives the most accurate reading if the coil up and down several
times.
Indicator
Mineralization
%Fe
3
O
4
Sensitivity
7 segments
High
Over 1
Over 2500
2
–6 segments
Medium
.026
– 1.0
61
– 2,500
1 segment
Very low
0.006 - .025
15
– 60
None
--
Lower than.006
Lower than 15
Magnetic susceptibility is expressed in micro-cgs units. In a saltwater environment without iron
minerals, the bar graph shows the relative electrical conductivity.
In soils where the value is higher than 10,000 micro-cgs, the device will be overloaded and will not be
usable. A possible solution is to hold the detector a few inches above the ground. Listen to the device
so that you can better detect how high you need to hold the coil.
High magnetic susceptibility is commonly found in soils that are composed of igneous rocks, in
floodplain black sand streaks on beaches, and in red clay soils of humid climates.
Low magnetic susceptibility is usually found in the white beach sands of tropical and subtropical areas
and soils above limestone.
